Biomedical subjects

B Kroker

Publications and source records attributed to B Kroker.

6 recordsLinked to original sources

PubMed2000

Validation of the POLY-MESAM seven-channel ambulatory recording unit.

STUDY OBJECTIVES: To determine the recording capabilities of the POLY-MESAM (PM) unit (MAP; Martinsried, Germany), an American Sleep Disorders Association level III system, and to compare it with simultaneous 12-channel polysomnography in the sleep laboratory. MEASUREMENTS AND RESULTS: Fifty-three patients (49 men and 4 women) with obstructive sleep-related breathing disorders of varying severity were included. The apnea-hypopnea indexes (AHIs) obtained using the two methods differed significantly from each other, although the correlation was close. The PM unit produced false-negative results in patients with mild to moderate obstructive sleep apnea (OSA). The sensitivity of the PM unit in detecting patients with an AHI > 10 was 92%, while the specificity was 96.3%. CONCLUSIONS: The correlation of AHIs obtained with polysomnography and with the PM unit is close. However, in some cases, the PM may underestimate OSA parameters. The PM unit produces false-negative results in patients with mild to moderate OSA. While inpatient polysomnography remains the "gold standard," the PM unit may provide an inexpensive alternative in some special cases.

Adult↗

PubMed1999

[What are the side-effects of nocturnal continuous positive pressure ventilation (nCPAP) in patients with sleep apnea for the head-neck region?].

BACKGROUND: Nasal continuous positive airway pressure ventilation therapy is the present gold standard in the treatment of obstructive sleep apnea. Depending on the definitions used, about 60% of the patients tolerate nCPAP therapy. The reason for this limited tolerance is a varying number of side effects. The aim of the present retrospective study was to analyze the incidence and intensity of otorhinolaryngological side effects of nCPAP therapy. METHOD: Questionnaires inquiring about the frequency of using nCPAP and objective and subjective complaints were sent to 92 patients who were treated with nCPAP in our department within the last years. Six of 92 patients also used a heated humidifier. A telephone interview was added to complete the questionnaires as correctly as possible. RESULTS: Eighty questionnaires were sent back completely answered. The mean frequency of using nCPAP (+/- standard deviation) was 6.8 +/- 1.6 hours per night and 6.5 +/- 1.4 nights per week. The mean duration of nCPAP therapy was 28.0 +/- 21.0 months; the mean pressure used was 6.8 +/- 1.2 cm H2O. The following side effects were specified most frequently: disturbance of sleep during the night (71.3%), dry mouth (47.5%), dry nose (46.3%), pressure marks by the mask (41.3%), crusts within the nasal cavity (38.8%), and hearing loss (26.3%). Dryness within the nose and mouth was considered the most irritating side effects. CONCLUSIONS: NCPAP therapy has a number of different side effects in the head and neck. These side effects are seen frequently. Prospective analysis must show whether there are correlations between the intensity and frequency of side effects and the duration of therapy, and whether technical improvements (quality of masks, noise reduction, humidifiers) are able to reduce the frequency of side effects.

Adult↗

PubMed1999

[Validating a 7-channel ambulatory polygraphy unit. 1: Operating instructions for the physician and patient].

PURPOSE: For some time, the ambulatory diagnosis of sleep-related breathing disorders has included the use of seven-channel recording units. One such unit is the POLY-MESAM (MAP, Martinsried, FRG). The first part of the present study prospectively investigated the handling of the system for physicians and patients, its technical reliability, reliability of the software used and the results in comparison to handscoring. METHODS: In all, 104 patients (95 males, 9 females) were studied for different severities of obstructive sleep-related breathing disorders. The first 51 patients were connected to the POLY-MESAM in the evening within the clinic. The patients then slept at home and returned the next day. Another 53 patients received only a short briefing in the clinic and connected themselves at home to the POLY-MESAM System. Each patient's status was monitored by means of a visual analogue scale. Automatic evaluation of the data was compared with the results of manual scoring. RESULTS: From the data recorded only 6% of the results were not usable. Patients acceptances of the system were very high (94.3%). On average each patient required 21 minutes for attaching and detaching the device. Scoring and instructing the patients required an average of 23 min. Regarding the apnea-hypopnea index (AHI), the correlation between automatic (AHI = 11.1) and manual (AHI = 11.3) evaluations was high. Analysis of snoring turned out to be insufficient. CONCLUSIONS: The POLY-MESAM proved to be reliable and user-friendly. Our findings show that the system can be recommended for outpatient screening of sleep-related breathing disorders, with patients able to manage the system without help. Validation by using simultaneous polysomnography is the subject of part two of the study.

Adult↗

PubMed1999

[Validating a 7-channel ambulatory polygraph unit. 2: Simultaneous polysomnography].

PURPOSE: For some time, the ambulatory diagnosis of respiratory disturbances during sleep has included the use of seven-channel recording units. One of these systems is the POLY-MESAM unit (MAP, Germany). METHODS: The aim of the present study was to validate the POLY-MESAM system by simultaneously performing 12-channel polysomnography. Forty-nine patients (45 males and 4 females) with different severities of obstructive sleep-related breathing disorders were included. Obstructive sleep apnea was diagnosed, when an apnea-hypopnea index (AHI) > 15 was found by polysomnography. The sensitivity and specificity for POLY-MESAM were calculated on the basis of the polysomnographic AHI. RESULTS: The sensitivity of POLY-MESAM for detecting patients with an AHI > 15 was 86.4% and the specificity was 100%. CONCLUSIONS: The POLY-MESAM system was easy to use. The sensitivity and specificity for the MESAM4 unit were 92% and 97% respectively, which was similar to POLY-MESAM. Additionally, POLY-MESAM provided the possibility for distinguishing the different kinds of apneas. Thus, POLY-MESAM was considered to be a useful development of the previous MESAM4 unit. In some cases, use of the POLY-MESAM unit resulted in underestimation of the AHI. POLY-MESAM produced false-negative results in patients with mild to moderate OSA. This finding was reflected in the relatively poorer sensitivity of the method (86.4%). Cardiorespiratory sleep studies (as possible with POLY-MESAM) are best limited to patients for whom the diagnosis of OSA is highly probable or as a follow-up tool in selected circumstances.

Computer Systems↗

PubMed1998

[Obstructive sleep apnea and obstructing nasal polyps].

BACKGROUND: Nasal obstruction may be a causative factor in the etiology of obstructive sleep apnea. No studies were found that dealt with the role of nasal polyps in sleep apnea. METHOD: Two male patients, 69 and 44 years old, were examined in our clinic because of nasal polyps occluding the nasal cavity. Their main complaint was nasal breathing obstruction with hyposmia. The clinical history revealed snoring but neither apnea nor daytime sleepiness was reported. Both patients underwent full nocturnal 12-channel polysomnography (PSG) prior to endonasal sinus surgery. PSG and nasal endoscopy were performed 3 months postoperatively. RESULT: The patients showed an increased apnea hypopnea index (AHI) from 21.1 to 76.6 and 7 to 38.8 respectively. Excessive daytime sleepiness (EDS) appeared and relative duration of REM sleep decreased. Nasal CPAP therapy was recommended. CONCLUSION: Although patients felt relieved after surgery since their nasal breathing problem was solved, the results with respect to AHI, EDS, and sleep pattern were unexpected. Perhaps these findings can be explained by surgical alteration of nasal receptors or by a postoperative switch from oral to nasal nocturnal breathing.

Adult↗

PubMed1997

Ventilation scintigraphy of the middle ear.

UNLABELLED: In this study, an attempt was made to administer radioactive gas into the tympanic cavity to measure initial gas trappings as well as clearance from the middle ear to evaluate eustachian tube function. METHODS: Twenty-eight patients were administered 50 MBq 133Xe gas. Three different methods for gas application were tested: (a) direct injection through a tympanostomy tube in two patients, (b) administration through a nasopharyngeal catheter combined with Valsalva maneuvers in six subjects without middle ear dysfunction and (c) insufflation into the pharyngeal space through a nose olive performed in 12 patients with normal eustachian tube function and in eight patients with one-sided tube dysfunction. RESULTS: All three approaches were successful in visualizing middle ear ventilation, demonstrating tracer trapping within the tympanic cavities in 20 of 28 patients. Semiquantitative evaluation by region of interest techniques revealed a left-to-right uptake ratio of 48.4%-51.6% in 13 patients without tube dysfunction. Five patients with one-sided tube dysfunction showed a significantly lower median uptake of 31.6% (p = 0.01). The clearance half-lives ranged from 9 to 283 min in normal subjects and 37-64 min in patients with one-sided tube malfunction, demonstrating no statistically significant difference between the two groups and a trend towards increased washout in patients with tympanic dysfunction. CONCLUSION: Middle ear ventilation scintigraphy with 133Xe through a nose olive is an easy-to-perform test to evaluate eustachian tube function and has a success rate of about 70%, thus, reflecting the complex physiological mechanisms involved.

Adult↗